Rubber coated wood



' Feb. 24, 1959 J, R, EHRL H 2,875,101

RUBBER COATED WOOD Filed July 29, 1954 INVENTOR. Joseph R. Ehrlich.

Maxwell E.Sporrow.

ATTORNEY.

treating the body or base of United States Patent 2,875,101 RUBBER COATED WOOD Joseph R. Ehrlich,New Yo;k,N.Y. p, A ucanonrmy 29, 1954, fierialNo. 446,669

" 3Claims. or. 117-448 This invention relates to article ofmanufacture comprising at least two members which are cohesively but not coalescingly attachable to each other, and the method of each of such members to' impartsuch quality to the same. i I have discovered that wood pieces or members treated according to this invention can bemade to adhere to each other temporarily lay-simply touching their surfaces 1 to- "gether; and that such members can be taken apart again and put together again, over again without the members losing theinproperty of adhesion and without the membersadhering' to any other surface than their own or members havin g similar surfaces, and without the surfaces of such members exhibitrepeating that procedure over and ing any stickiness or tack to the touch. Such treated wood members have no surface tack, that is, they arenot tacky, adhere strongly to'each other arid the members may be separatedwithout injury to their surfacesf An important feature is that theskins of the respective members when the latter are brought together adhere-toeach other Without any coalescent action. In the manner-of the present invention, smoothness, resilience, flexibility and tautnessof the skin enable the contacting members to touch each other completely and without any "space between the contacting surfaces; and the adhesion 'of' the skins to their respective wood bases isL stronger than the cohesion developed betweenthe said sk ins when the members arebrought together. i 1 It" is an object of thepresent inventionto provide an assembly comprising at least two members treated in such al 'manner that they may be made toengage eachiother by touching their surfaces together through cohesive -at-.

traction and not coalescence and which are'then'readily disengageable' without destroying or injuring the engaging surfaces. V

It is another object of the prsenbinventioir toiprovide an article of manufacture comprising a plurality of wood elements the surfaces of which are capable of absorbing moistureyanda casing completely covering each of'the "illustrates the production of some satisfactory products of .many which may be obtained as a result of the knowledge gained through or gleaned from an understanding of the invention; and it is further intended that there be included, 'as part of the invention all such obvious changes and modifications thereof as would occur to a person -wooden piece according to the invention;

Fig. 2; is a sectional view taken on line 2 2 of Fig. 1; 13 d i i Fig. 3is a much enlarged end view of two wooden pieces shown in Fig. 1, in the process of beingseparated by hands. i

In order toimpart tothe articles the aforementioned properties, itisimportant for best results to select Wood members having moisture absorbingsurfaces, that is, the surfaces of the wood members should be porous, not covered with varnish, lacquer or other sealing material. These wood pieces or members are eachenca'sed completely with a non-tacky, tight-fitting, elastic, flexible, shrinkable and resilient skin which is preferably thin, transparent, non-visible and hardly noticeable. This skin issolidly and completely anchored to the wood member or base as long asthe casing is complete, uninjured and has holoose ends. Y i i i V Pressure sensitive adhesives commonly in use at present are permanently tacky without being moistened and adhereto anynon-tacky, dry surface under light pressure, and caneasily be removed therefrom without any traces left on the applied surface. facesof the articles to whichthe pressure sensitive ad- 'hesive is applied are brought into contact with each other, the two surfaces will not merely cohere but will coalesce and cannot be readily pulled apart without injury to the surfaces. In other words, these-contacting surfaces due to coalescence, will have to be virtuallyftorn apart in order to separate them from each other. i There arewellknown self-sealing adhesives which are hon-tackybdo not adhere to dry, non-tacky surfaces, but coalesce, however, if pressed together. Such dry adhesives are used, for example, in the shoe and envelope-making industries. However,fwhen such surfaces are pressed togetlier tli'ey produce strong and permanent bonds and the members having suchadhesivesurfaces cannot be pulled' 'apart without at least impairment to or peeling off elements, the casingconsisting of a. flexible, non-tacky,

non-coalescing, resilient and elastic skin tightly shrunk *on the element, the casings being adaptedwhen the elements arebrought together under slight pressuretocohere Without tack or coalescence and 'being readily andrepeatedly separatable from each other without separating fromtheirrespective elements. it i i i i i It is still another objectof the. present vinvention to make the skinsin the form of at'ransparent film.

Yet another object of the present invention resides 'in the method of making or producing suchkarticlesw These and other objects andadvantag e's of the invention'will appear as the description proceeds, it beingunderstood, however, that it is not intended thattlie invention be, limited to the exact details described herein which and, in fact, in manyinstances, injuring the fibers-of the members to-which the adhesive is applied. V

i In the practice of the present invention, the two types of adhesives just referred to are definitely to be avoided. The type of adhesive employed to form a skin encasing the wooden members must be non-tacky, must form a skin or surface which will not adhere to any skin or surface ex cept to a skin or surface of thesame kind, must form a skin which is elastic, flexible, non-tacky, shrinkable, resilient and tight-fitting and so strongly anchorable to its baseor member, that contact and separation of the bonded surfaces canbe repeated many times without injury to the surfaces, and'the skins orsurfaces remain dry and clean after each separation. It has been found that an adhesive comprising a non-vulcanized rubber interspersed with particles of film-forming material that breaks the-coalescence of the surfaces or skins when formed, thatis, that prevents coalescence of the skins, satisfies the foregoing requirements. M w 1 a 1 Patented Feb. 24, 1959 However, if the tacky sur- As an exampleof carrying out the invention, in neatly cut pieces or members of wood with a smooth, but absorbent surface, non-rusting. clean pins are driven into one far end of the pieces or members about one-eighth inch deep. These pinned wooden members are dipped into the dipping solution so that they are completely immersed and deep enough that about one-eighth inch of the free end of the pin is also immersed. The solution forms a substantially white coating which turns transparent when dry. To remove the pin, the wooden member is pulled down straight. The skin covering the lower part of the pin slides off the pin easily, provided that the latter was clean before dipping. This little protruding part of the skin contracts immediately and closes over the tiny hole caused by the insertion of the pin. Thus, the wooden piece or member is totally and completely encased by the skin, and the latter is anchored to the Wood.

Another method of producingv an endless casing, that is, a casing without free or loose ends where peeling could possiblystart, is by performing the dipping operation in two steps, namely, dipping one portion first in the solution, then permitting this portion to dry completely to form a skin; then turning the member around and dipping the other, undipped portion in the solution in such a manner that the second dip slightly overlaps the first dipped portion and then permitting the second dipped portion to dry; thus now forming acompletely sealed and endless skin over all of the surfaces of the member without any lose ends or edges.

The dipping liquid or solution may comprise, ,for example, a blend of two-thirds of a water solution containing 5% by weight of water-soluble methylcellulose and one-third of a natural rubberlatex ,of 38% to 40% by Weight of solid contents. The methylcellulose should be of low viscosity, e. g. five to fifteencps. The blend should have a pH not less than 8.5, and may ,ormaynot contain de-foaming agents, wetting agents, anti-oxidants or other additives. The latex dispersion in the methylcellulose solution is not stable and has a tendency to'separate. Therefore, high speed agitation before dipping is necessary in order to have the methylcellulose well interspersed within the dry rubber skin. In the preceding example, the ratio of solid methylcellulose to solid rubber inthe dry skin can be calculated to be between 1 to 3.8 to

l to 4. Depending upon the type of latex employed, the

manner in which it was processed, etc., it might be nccessary to change the ratio of the solid contents. of the components in the dry skin. Using a 60% centrifuged latex, water will have to be added to the blend and'the ratio of methylcellulose to rubber mightbe 110 6.

It is preferred to use methylcellulose because it strengthens the rubber skin more than other;film-forming additives which likewise would prevent tack and coalescence of the rubber skin. However, there-can also be used sodium carboxy methylcellulose, hydroxy ethylcellulose, carboxy methyl hydroxy ethylcellulose, water soluble metal poly acrylates and other non-tacky water soluble, film-forming materials in whose Water solutions or dispersions latex is dispersible without coagulation.

The skin or casing as produced in the aforesaid ,ex-

amples, has no cold flow, is non-tacky to the touch and .does not adhere to any other surface but one of its own type. When it adheres to its own surface, it does not coalesce as a plain non-vulcanized rubber skin might do; such coalescence does not take place at room temperature, and not even over any extended period of time or under moderate pressure. Any pressure-sensitive adhesive of any denomination, or self-sealing adhesive or heat sealing adhesive would coalesce under the aforementioned conditions. Neither could any such adhesive skins or surfaces be separated from each other without causing injury to the skin or film, or without being pulled ofi its base, wholly or in part. The encased wooden pieces or .members must have the property to be. capable of adhering'to each other and be separated over and over again without hering to the wooden piece with an adhesive Having thus described the invention,

any injury tothe skinencasing the member and as often as desired, regardless of season or atmospheric conditions and over a long period of time.

Articles made according to the invention may be employed for several purposes and uses, for example, construction toys, model furniture, houses, machines and other objects. These articles or members may also be used to form letters, figures, etc., for educational as well as for window display purposes and also for constructing anatomical models. The parts or members may be taken apart, rearranged, or reassembled as frequently as it is desired. The membersmay further be used to temporarily adhere one to another when made in the form of game pieces or to a board upon which the game is played.

Figs. 1 and 2 of the drawings show a woodenpiece made according to the inventioninwhich the numeral 10 represents the body of the wooden piece completely covered or encased in a non-toxic, resilient, thin, dry and preferably non-tacky and non-glossy coating, skin or casing 12, which is preferably of such thickness as to be substantially invisible to the naked eye. As heretofore stated, an example of such coating or-casing material comprises a natural unvulcanized rubber and methyl cellulose. Fig. 3 shows two such encased or coated wooden pieces being separated at 14 by the hands 15. The adhesive strength of coating 12 to itswooden body 10 is at least equal to, but preferably greater than the strength created by the pull, which is necessary to separate the two .water soluble etherbeing in such ratio whereby when two such wooden coated pieces are pressed together slightlythey will ,adhere to each other without coalescence of the ,coatingmaterial of the two pieces, the coating adstrength at least equal to the pull necessary to separate the two pieces whereby thesaid pieces may be re-united and re separated a great many times without impairing the coatings.

While the invention has been described with respect to particular embodiments or examples which give satisfactoryresults, it'will be understood by those skilledin the art after understanding the invention, that various changes and modifications may be made without departingfrom the spirit and scope of the invention and it is intended, therefore, in the appended claims to cover all such changes and modifications.

new and desired to secure by Letters Patent is:

1. As an article of manufacture, a'wooden piece com- ;pletely covered with a coating consisting essentially of natural unvulcanized rubberinterspersed w1th a water soluble cellulose ether, the said natural unvulcan zed rubber and the said water soluble cellulose ether being in such ratio whereby when two suchwooden coated pieces are pressed-together slightly they Willadhere to each other without coalescence of the coating material of the two pieces, the coating adhering to the wooden piece with an adhesive strength at least equal to the pull necessary to separate the twopieces whereby the said pieces may bereunited and re-separated a great many times without impairingthetsaidcoatings.

2. 'As anarticle of manufacture, a wooden piece according to claim 1, and wherein said coating consists essentiallyof natural unvulcanized rubber and methyl cellulose. a a i 3. As an article of manufacture, a wooden p1ece acwhat is claimed as References Cited in the file of this patent, UNITED STATES PATENTS 1,560,172 Chamberlain Nov. 3, 1925 2,065,439 Fischer Dec. 22, 1936 2,199,700 Gramelspacher May 7, 1940 6 Mark Apr. 7, 1942 Elemdorf Feb. 21, 1950 Dickey Feb. 19, 1952 Heggedal Feb. 19, 1952 ONeill July 7, 1953 Mahler Jan. 18, 1955 FOREIGN PATENTS Italy of 1939 

1. AS AN ARTICLE OF MANUFACTURE, A WOODEN PIECE COMPLETELY COVERED WITH A COATING CONSISTING ESSENTIALLY OF NATURAL UNVULCANIZED RUBBER INTERSPERSED WITH A WATER SOLUBLE CELLULOSE ETHER, THE SAID NATURAL UNVULCANIZED RUBBER AND THE SAID WATER SOLUBLE CELLULOSE ETHER BEING IN SUCH RATIO WHEREBY WHEN TWO SUCH WOODEN COATED PIECES ARE PRESSED TOGETHER SLIGHTLY THEY WILL ADHERE TO EACH OTHER WITHOUT COALESCENE OF THE COATING MATERIAL OF THE TWO PIECES, THE COATING ADHERING TO THE WOODEN PIECE WITH AN ADHESIVE STRENGTH AT LEAST EQUAL TO THE PULL NECESSARY TO SEPARATE THE TWO PIECES WHEREBY THE SAID PIECES MAY BE REUNITED AND RE-SEPARATED A GREAT MANY TIMES WITHOUT IMPARING THE SAID COATINGS. 